The objective of this clinical pharmacokinetic study is to evaluate the effects of intravenous erythromycin on the pharmacokinetic disposition of cyclosporine, and to determine the effect of route of erythromycin administration on the cyclosporine kinetics. The investigator intends to perform all technical aspects of the study, but will utilize the GCRC staff when necessary. Also, the GCRC will be used to house the subjects during overnight stays, to provide a core lab for sample processing and to provide dietary support.